Former prime minister Julia Gillard will answer questions about a union slush fund run by her former boyfriend at a royal commission.

Former prime minister Julia Gillard will appear before the Royal Commission into Trade Union Governance and Corruption in September.

Ms Gillard will be questioned in relation to a slush fund operated by her former boyfriend, Bruce Wilson, when Mr Wilson was an official of the Australian Workers’ Union in the early 1990s.

Ms Gillard was a lawyer with the firm Slater and Gordon at the time and did work advising the union, including advising on the setting up of the fund.

Witnesses at the commission have testified Mr Wilson gave Ms Gillard money from the slush fund to pay for renovations to her house.

Ms Gillard has repeatedly denied the claims.

In a statement on Thursday the Royal Commission said Ms Gillard’s lawyers “have been advised of a hearing date in early September”.

The Australian newspaper has reported that judge Bernard Murphy, who was Ms Gillard’s boss at Slater and Gordon, will also be called to give evidence.